JP6063960B2 - Manufacturing method of multilayer optical information recording disk - Google Patents

Description

The present invention relates to a method of manufacturing a multi-layer optical information recording disk.

  In recent years, as a technique for increasing the capacity of an optical information recording disk, it has been studied to increase the number of recording layers for recording information. For example, Non-Patent Document 1 discloses a substrate on which a sheet having two recording layers and two intermediate layers is manufactured, punched into a disk shape, and a guide layer for performing tracking servo on the punched sheet is formed. A technique for realizing a multi-layered recording layer by pasting together is disclosed.

Tatsuo Mikami et al., `` 20-Layer Optical Disc Fabricated with web coating and laminating process '', Th-M-01, ISOM'12, p.200-201

  By the way, a conventional multilayer optical information recording disk having a multi-layered recording layer has a guide layer and a recording layer separated from each other, so that a laser beam for performing tracking servo on the disk and recording / reproduction are performed. There is a problem that it is necessary to irradiate at least two laser beams, and the optical system and control of the recording / reproducing apparatus are complicated. For this reason, it has been impossible to perform tracking and recording / reproducing with a single laser beam using a conventional recording / reproducing apparatus for an optical information recording disk.

  Also, the conventional multilayer optical information recording disk can trace the recording layer track with good reproducibility due to the influence of the warp of the disk and the change of the disk position with the loading and unloading of the disk because the guide layer and the recording layer are separated. For example, when recording is performed halfway through one recording layer, there is a problem that it is difficult to perform recording from the continuation in the recording layer.

The present invention has been made in view of the above background, and is a multilayer optical information recording disc capable of tracking and recording / reproducing with a single laser beam, and capable of tracing a recording layer with good reproducibility . Providing a manufacturing method is one aspect of the present invention.

  Specifically, according to one or more embodiments of the present invention, a multilayer optical information recording disk comprising a plurality of recording layers and an intermediate layer provided between the plurality of recording layers, adjacent to the recording layer At least one of the intermediate layers is made of an adhesive, and the recording layer contains a polymer binder and a dye dispersed in the polymer binder, or contains a polymer to which the dye is bound, and the dye is recorded. Information is recorded by forming a convex shape toward the intermediate layer that is deformed by the heat generated by absorbing light and forming the intermediate layer made of the adhesive, and the interface with the intermediate layer made of the adhesive A multilayer optical information recording disk having a groove for performing tracking servo is provided.

  According to such a configuration, since a groove for performing tracking servo is formed in each recording layer, tracking and recording / reproduction by one laser beam can be performed. Further, since each recording layer has a groove for performing tracking servo, it becomes possible to trace the track of the recording layer with good reproducibility.

  In the multilayer optical information recording disk described above, the intermediate layer adjacent to one side of the recording layer is a first intermediate layer made of an adhesive, and the intermediate layer adjacent to the other side of the recording layer is more than the first intermediate layer. It can be set as the structure which is a hard 2nd intermediate | middle layer.

  According to this, it is possible to easily form a convex shape at the interface between the recording layer and one intermediate layer (first intermediate layer).

  In the multilayer optical information recording disk described above, the difference in refractive index between the recording layer and the first intermediate layer is preferably larger than the difference in refractive index between the recording layer and the second intermediate layer.

  According to this, since the interface between the recording layer and the first intermediate layer on which the convex shape is formed is used for reading information, the interface reflectance is relatively large due to the large refractive index difference between the materials on both sides of the interface. It becomes easier to read information, and the interface between the recording layer and the second intermediate layer where the convex shape is not formed is not used for reading information, so by reducing the refractive index difference between the materials on both sides of the interface, It is possible to increase the transmittance of light used for recording / reading (hereinafter referred to as recording / reading light), specifically, the transmittance of both interfaces. As a result, when the recording layer is multi-layered, light can reach a recording layer deep as viewed from the recording-reading light irradiation side, which is advantageous in increasing the recording capacity by multi-layering.

  In the multilayer optical information recording disk described above, it is more desirable that the refractive index of the recording layer and the refractive index of the second intermediate layer are substantially the same.

  According to this, since the reflectance of light at the interface between the recording layer in which the convex shape is not formed and the second intermediate layer becomes substantially 0, when the recording layer is multi-layered, the recording / reading light is made deeper. Since the recording layer can reach the recording layer, it is advantageous to increase the recording capacity by multilayering.

  In the multilayer optical information recording disk described above, the intermediate layer adjacent to the recording layer may be made of an adhesive, and the intermediate layer made of the adhesive and the recording layer may be alternately arranged.

  According to this, convex shapes can be formed at both interfaces of one recording layer. Thus, for example, when the number of recording layers is the same as that of a disc having a convex shape formed only on one interface of the recording layer, the recording capacity can be increased, and the number of recording layers can be increased. However, even when the number of the recording layers is smaller than that of the disk in which only one interface of the recording layer is formed, it is possible to realize a recording capacity equivalent to that of the disk.

Further, as a method for producing a multilayer optical information recording disk comprising a plurality of recording layers and an intermediate layer provided between the plurality of recording layers , a polymer binder and a dye dispersed in the polymer binder are contained. Or a step of forming a groove by thermal imprinting on the surface of a recording layer containing a polymer to which a dye is bonded, and an intermediate layer made of an adhesive is formed on the surface of the recording layer on which the groove is formed. Proposing a method for producing a multilayer optical information recording disk, comprising: a step of obtaining a multi-layer sheet including an intermediate layer made of an adhesive and a step of bonding a multi-layer sheet to another multi-layer sheet .

The recording layer includes a plurality of recording layers and an intermediate layer provided between the plurality of recording layers, and the intermediate layer adjacent to one side of the recording layer is a first intermediate layer made of an adhesive, As a method for producing a multilayer optical information recording disk, wherein the intermediate layer adjacent to the other side is a second intermediate layer harder than the first intermediate layer , the second intermediate layer, the polymer binder, forming a groove and it contains the polymeric binder dispersed dye, or a step of forming a recording layer containing a dye is bonded polymer in this order by thermal imprinting on the surface of the recording layer To obtain the first sheet, to form the first intermediate layer on the second release sheet to obtain the second sheet, and to bond the first intermediate layer and the recording layer together. A step of superimposing a second sheet on the sheet to obtain a third sheet; Removing the first release sheet from the third sheet and forming a recording layer on the exposed second intermediate layer; and forming a groove on the surface of the exposed recording layer by thermal imprinting. A method of manufacturing a multilayer optical information recording disk is provided, which includes a step of obtaining four sheets and a step of bonding the fourth sheet to another fourth sheet.

The recording layer includes a plurality of recording layers and an intermediate layer provided between the plurality of recording layers, and the intermediate layer adjacent to one side of the recording layer is a first intermediate layer made of an adhesive, As a method for producing a multilayer optical information recording disk in which the intermediate layer adjacent to the other side is a second intermediate layer that is harder than the first intermediate layer , a polymer binder and a polymer binder are respectively formed on both surfaces of the second intermediate layer. A step of forming a recording layer containing a dispersed dye or a polymer to which a dye is bonded, a step of simultaneously forming a groove on the surface of each recording layer by thermal imprinting, and a release sheet. Forming a first intermediate layer to obtain a fifth sheet; obtaining a sixth sheet by bonding the first intermediate layer of the fifth sheet to one recording layer; and Bonding to another sixth sheet; We propose a method for manufacturing a multi-layer optical information recording disk, characterized by.

  According to the method as described above, it is possible to manufacture a multilayer optical information recording disk in which each recording layer has a groove for performing tracking servo, so that tracking and recording / reproducing can be performed with one laser beam, and It is possible to trace the recording layer track with good reproducibility. Further, since the grooves can be easily formed in the recording layer by thermal imprinting, it becomes possible to manufacture a multilayer optical information recording disk having a groove for each recording layer to perform tracking servo at a relatively low cost.

  In the above-described method for producing a multilayer optical information recording disk, the glass transition temperature of the recording layer is Tg [° C.], and at least one of the thermal imprint mold and the recording layer is heated to Tg ± 25 ° C. during thermal imprinting. Is desirable.

  In the above-described method for manufacturing a multilayer optical information recording disk, it is desirable to press a thermal imprint mold against the recording layer at a pressure of 0.1 MPa or more.

  In the manufacturing method of the multilayer optical information recording disk described above, the step of obtaining the fourth sheet is to cut the recording layer and the intermediate layer into a predetermined shape simultaneously with the formation of the groove by pressing the thermal imprint mold. It may be.

  According to this, since the manufacturing process can be reduced as compared with the case where thermal imprinting and cutting (punching) are performed separately, the productivity of the multilayer optical information recording disk can be improved.

It is a figure which shows the cross-section of the multilayer optical information recording disc based on one Embodiment. It is a figure explaining the recording mark formed by recording of information on a disc, and recording of information. It is a figure explaining reproduction | regeneration of the information recorded on the disc. It is figure (a)-(c) explaining the 1st example of a disc manufacturing method. It is figure (a)-(d) explaining the 1st example of a disc manufacturing method. It is a figure (a) and (b) explaining the 1st example of a disc manufacturing method. It is figure (a)-(e) explaining the 1st example of a disk manufacturing method. It is figure (a)-(c) explaining the modification of a 1st example. It is figure (a)-(d) explaining the 2nd example of a disc manufacturing method. It is a figure which shows an example of the thermal imprint apparatus used at the thermal imprint process of the 2nd example of a disc manufacturing method. FIG. 4A is a plan view of a resin sheet after thermal imprinting, and FIG. 4B is a diagram illustrating a state where a positioning mark on one recording layer is shifted from a positioning mark on the other recording layer. It is figure (a), (b) explaining the modification of a 2nd example. FIG. 6A is a diagram showing a cross-sectional structure of a multilayer optical information recording disk according to another embodiment, and FIG. 6B is a diagram for explaining a method of forming grooves on both interfaces of the recording layer. FIG. 3B is a diagram showing an AFM image (a) of a groove formed on a recording layer by thermal imprinting and a profile of an A-B cross section of the AFM image.

Next, an embodiment of the present invention will be described with reference to the drawings.
Note that the drawings referred to in the following description are schematic diagrams for explaining the present invention and do not reflect actual dimensions or the like.

<Configuration of multilayer optical information recording disk>
As shown in FIG. 1, a multilayer optical information recording disk 10 according to this embodiment includes a substrate 11, a plurality of recording layers 14, a plurality of intermediate layers 15 (a first intermediate layer 15A and a second intermediate layer 15B). The cover layer 16 is provided. In the following description, the interface formed between the recording layer 14 and the first intermediate layer 15A is referred to as a first interface 18A, and the interface formed between the recording layer 14 and the second intermediate layer 15B. Is called the second interface 18B.

  The substrate 11 is a support for supporting the recording layer 14, the intermediate layer 15, and the like, and is made of, for example, a polycarbonate disk. In the present invention, the material and thickness of the substrate 11 are not particularly limited.

The recording layer 14 is a layer made of a photosensitive material on which information is optically recorded, and has a groove 14A formed in a spiral shape or a concentric shape on the first interface 18A that is an interface with the first intermediate layer 15A. doing.
The groove 14A is a groove for performing tracking servo for adjusting the focal position of the recording / reading light so that the recording / reading light can be accurately irradiated onto the track extending in the circumferential direction of the recording layer 14 at the time of recording or reproducing information. In the present invention, the shape, width, depth, pitch, and the like of the groove can be used for tracking servo and can be arbitrarily set as long as they can be formed by thermal imprint described later, and are set as appropriate according to the use of the disk. can do. As an example, the groove 14A has a width of 160 nm, a depth of 60 nm, and a pitch of 320 nm.

  In the present embodiment, the recording layer 14 includes a polymer binder and a dye dispersed in the polymer binder.

  Examples of the polymer binder used for the recording layer 14 include polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), polyethyl methacrylate, polybutyl methacrylate, polybenzyl methacrylate, polyisobutyl methacrylate, polycyclohexyl methacrylate, and polycarbonate (PC). ), Polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyvinyl benzoate, vinyl polypivalate, polyethyl acrylate, polybutyl acrylate, cycloolefin polymer, and the like.

  On the other hand, examples of the dye used for the recording layer 14 include a dye (one-photon absorption dye) conventionally used as a heat mode type recording material. In order to minimize the influence on the adjacent recording layer 14 at the time of recording / reproduction, it is desirable to include a multiphoton absorption dye as the dye, and the multiphoton absorption dye is, for example, linear with the wavelength of the readout light. A two-photon absorption dye having no absorption band is preferable.

  Specifically, examples of the one-photon absorption dye include methine dyes (cyanine dyes, hemicyanine dyes, styryl dyes, oxonol dyes, merocyanine dyes, etc.), macrocyclic dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), azo Dyes (including azo metal chelate dyes), arylidene dyes, complex dyes, coumarin dyes, azole derivatives, triazine derivatives, benzotriazole derivatives, benzophenone derivatives, phenoxazine derivatives, phenothiazine derivatives, 1-aminobutadiene derivatives, cinnamic acid derivatives, quinophthalone And pigments.

  The two-photon absorption dye is not particularly limited as long as it does not have a linear absorption band in the wavelength of the readout light, and examples thereof include compounds having a structure represented by the following general formula (1). Can do.

(In the general formula (1), X and Y each represent a substituent having a Hammett's sigma para value (σp value) of zero or more, which may be the same or different, and n represents an integer of 1 to 4. R represents a substituent, which may be the same or different, and m represents an integer of 0 to 4.)

  In the general formula (1), X and Y are those having a positive σp value in the Hammett formula, so-called electron-withdrawing groups, and preferably, for example, a trifluoromethyl group, a heterocyclic group, a halogen atom, a cyano group Nitro group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, carbamoyl group, acyl group, acyloxy group, alkoxycarbonyl group and the like, more preferably trifluoromethyl group, cyano group, acyl group, acyloxy group, or An alkoxycarbonyl group, most preferably a cyano group or a benzoyl group. Among these substituents, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, a carbamoyl group, an acyl group, an acyloxy group, and an alkoxycarbonyl group are further added for various purposes in addition to providing solubility in a solvent. It may have a substituent, and preferred examples of the substituent include an alkyl group, an alkoxy group, an alkoxyalkyl group, and an aryloxy group.

n is preferably 2 or 3, most preferably 2. As n becomes 5 or more, linear absorption comes out on the longer wavelength side, and non-resonant two-photon absorption recording using recording light in a wavelength region shorter than 700 nm becomes impossible.
R represents a substituent, and the substituent is not particularly limited, and specific examples include an alkyl group, an alkoxy group, an alkoxyalkyl group, and an aryloxy group.

  Although it does not specifically limit as a specific example of the compound which has a structure represented by General formula (1), For example, the compound of following chemical structural formula D-1-D-21 etc. can be mentioned.

  The dye as described above is preferably contained in the recording layer in an amount of 1 to 80% by mass, more preferably 5 to 60% by mass, and further preferably 10 to 40% by mass.

  When the recording layer 14 is irradiated with the recording light, the polymer binder is deformed by the heat generated by the dye absorbing the recording light, and the first interface 18A, more specifically, the adjacent grooves 14A, Information is recorded by forming a convex shape (recording mark M) toward the first intermediate layer 15A on the convex portion 14B between 14A. The recording mark M has a concave shape around the convex shape from the recording layer 14 toward the first intermediate layer 15A and a concave shape toward the recording layer 14 from the first intermediate layer 15A (a concave shape with reference to the first interface 18A before deformation). ) May be included.

  In order to record the information as described above, the recording layer 14 is formed thicker than a conventional recording layer containing a polymer binder and a dye, and one recording layer 14 has a thickness of 100 nm to 5 μm. Preferably, it is formed with a thickness of 100 nm to 3 μm, more preferably 200 nm to 2 μm. When the thickness is smaller than 50 nm, for example, the interface between the recording layer and the intermediate layer is deformed into a concave shape with reference to the recording layer as in the known recording technology by deformation of the recording layer, but the thickness is 100 nm. By the above, it deform | transforms so that the center of the recorded location may become convex. On the other hand, the upper limit of the thickness of the recording layer 14 is not particularly limited, but in order to increase the number of recording layers 14 as much as possible, the thickness of the recording layer 14 is preferably 5 μm or less. In the present embodiment, the thickness of the recording layer 14 is 400 nm (0.4 μm) as an example.

  A plurality of, for example, about 2 to 100 recording layers are provided. In order to increase the storage capacity of the multilayer optical information recording disk 10, it is desirable that the number of recording layers 14 is large, for example, it is desirable that the number of recording layers 14 is 10 or more. The recording layer 14 is made of a material that does not substantially change the refractive index before and after recording for deforming the first interface 18A.

  The recording layer 14 preferably has an absorptance (1 photon absorptance) with respect to recording light of 10% or less per layer. Further, in order to increase the number of recording layers 14, it is preferable that the absorption rate is as small as possible as long as recording is possible. Therefore, the absorption rate of the recording layer 14 is more preferably 8% or less, and 5% or less. More preferably, it is more preferably 3% or less. For example, on condition that the intensity of the recording light reaching the innermost recording layer 14 is 50% or more of the intensity of the irradiated recording light, in order to realize the eight recording layers, the recording layer 1 This is because the absorptance per layer needs to be 8% or less, and in order to realize 20 recording layers, the absorptance per recording layer needs to be 3% or less. When the absorptance is high, the number of layers is reduced, and the effect of increasing the recording capacity due to multilayering is reduced.

  Although details will be described later, the recording layer 14 described above is formed into a layer by applying a solution obtained by dissolving a dye material and a polymer binder in a solvent by a spin coating method or a blade coating method and curing it. It can be formed by pressing a mold (which is a mold for imprinting, also referred to as a stamper, a template, or the like) having a convex portion in which the shape of 14A is reversed and performing thermal imprinting. As a solvent for dissolving the dye material and the polymer binder, dichloromethane, chloroform, methyl ethyl ketone (MEK), acetone, methyl isobutyl ketone (MIBK), toluene, hexane, propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, or the like may be used. it can.

  The intermediate layer 15 is provided between the plurality of recording layers 14, in other words, adjacent to the top and bottom of each recording layer 14. More specifically, the intermediate layer 15 includes a first intermediate layer 15A adjacent to one side of the recording layer 14 and a second intermediate layer 15B adjacent to the other side of the recording layer 14, and includes a plurality of recording layers 14. The first intermediate layer 15A and the second intermediate layer 15B are alternately arranged therebetween. In the present embodiment, when viewed from the substrate 11 side, the first intermediate layer 15A, the recording layer 14, the second intermediate layer 15B, and the recording layer 14 are repeatedly arranged in this order.

  Each intermediate layer 15 is provided in order to provide a predetermined amount of space between the recording layers 14 so that interlayer crosstalk does not occur between the plurality of recording layers 14. For this reason, the thickness of each intermediate layer 15 is preferably 2 μm or more, and more preferably 5 μm or more. Each intermediate layer 15 is preferably thin as long as interlayer crosstalk does not occur. For example, the thickness is preferably 20 μm or less. In the present embodiment, the thickness of each intermediate layer 15 is 10 μm as an example. In addition, since the thickness of the first intermediate layer 15A and the second intermediate layer 15B is the same as 10 μm, the pitch of the first interface 18A is constant at 10 μm, 10.8 μm, 10 μm, 10.8 μm,. Absent. As a result, reproduction light that is reflected light from the first interface 18A being reproduced (light including a reproduction signal generated by irradiation of the readout light) and reading at the first interface 18A adjacent to the first interface 18A being reproduced are read. The influence of interference with the reflected light on the reproduction light can be reduced.

  Each intermediate layer 15 is made of a material that does not change due to laser irradiation during recording and reproduction. Further, each intermediate layer 15 is preferably made of a resin that is transparent to recording light, reading light, and reproducing light in order to minimize loss of recording light, reading light, and reproducing light. The term “transparent” here means that the absorptance is 1% or less.

  The first intermediate layer 15 </ b> A is made of an adhesive having adhesiveness that enables attachment to another surface, and is a softer layer than the recording layer 14. For example, the first intermediate layer 15 </ b> A has a glass transition temperature lower than that of the recording layer 14. Thus, by using the first intermediate layer 15A, which is softer than the recording layer 14, as the intermediate layer 15 adjacent to one side of the recording layer 14, when the recording layer 14 is heated and expanded by the recording light, the intermediate layer 15A is intermediate. The layer 15 is easily deformed, and the first interface 18A can be easily deformed. In addition, the comparison of the hardness of the recording layer 14 and the intermediate | middle layer 15 can be confirmed by mutually pressing the bulk body of the material which comprises each. Specifically, it can be confirmed that when the bulk bodies are pressed against each other, it is softer to be greatly recessed.

  On the other hand, the second intermediate layer 15B is a harder layer than the first intermediate layer 15A. The second intermediate layer 15B is formed of an ultraviolet curable resin, polycarbonate, or the like. In the present embodiment, the second intermediate layer 15B is as hard as the recording layer 14 or harder than the recording layer 14. For example, the glass transition temperature of the second intermediate layer 15 </ b> B is equal to or higher than the glass transition temperature of the recording layer 14. Thus, by using the second intermediate layer 15B having the same hardness as the recording layer 14 or harder than the recording layer 14 as the intermediate layer 15 adjacent to the other side of the recording layer 14, the multilayer optical information recording disk 10 is Due to the irradiation of the recording light, the convex shape is not formed on the second interface 18B, but the convex shape (record mark M) is formed only on the first interface 18A.

In the present embodiment, the first intermediate layer 15A and the second intermediate layer 15B have different refractive indexes, and the recording layer 14 and the second intermediate layer 15B have substantially the same refractive index. Specifically, in the recording layer 14 and the second intermediate layer 15B, the refractive index of the recording layer 14 is n1, and the refractive index of the second intermediate layer 15B is n3.
((N3−n1) / (n3 + n1)) ² ≦ 0.0003
It is desirable that the reflectance at the second interface 18B is equal to a certain degree of 0.0003 (0.03%) or less.

The refractive index of the recording layer 14 and the refractive index of the second intermediate layer 15B are preferably close values in order to eliminate reflection at the second interface 18B, and the difference is preferably 0.05 or less, more preferably It is 0.03 or less, more preferably 0.01 or less, and most preferably 0. As an example, the refractive index n1 of the recording layer 14 is 1.565, and the refractive index n3 of the second intermediate layer 15B is 1.564. At this time, the reflectance ((n3−n1) / (n3 + n1)) ² at the second interface 18B is substantially zero.

On the other hand, the recording layer 14 and the first intermediate layer 15A have different refractive indexes, and it is preferable that the difference between the refractive indexes of the two is moderate. As a result, the reading light can be reflected by the sudden change in the refractive index at the first interface 18A. More specifically, the difference in refractive index between the recording layer 14 and the first intermediate layer 15A is larger than the difference in refractive index between the recording layer 14 and the second intermediate layer 15B, and is 0.11 or less. preferable. Specifically, the refractive index of the recording layer 14 and the refractive index of the first intermediate layer 15A are expressed as follows, where n2 is the refractive index of the first intermediate layer 15A.
0.0005 ≦ ((n2−n1) / (n2 + n1)) ² ≦ 0.04
It is desirable that the reflectance at the first interface 18A be different to some extent between 0.0005 (0.05%) and 0.04 (4%).

When the reflectance is 0.0005 or more, the amount of reflected light at the first interface 18A can be increased, and the S / N ratio can be increased during information reproduction. In addition, since the reflectance is 0.04 or less, the amount of light reflected at the first interface 18A is suppressed to an appropriate level, and the recording / reading light is not greatly attenuated during recording and reproduction. 14 can be reached. This makes it possible to increase the capacity by providing a large number of recording layers 14. As an example, the refractive index n1 of the recording layer 14 is 1.565, and the refractive index n2 of the first intermediate layer 15A is 1.477. At this time, the reflectance ((n2-n1) / (n2 + n1)) ² at the first interface 18A is 0.0008 (0.08%).

  By adjusting the refractive index of the recording layer 14 and each intermediate layer 15 as described above, the light transmittance of the first interface 18A and the second interface 18B can be increased. Further, the light can reach the recording layer 14 deep as viewed from the irradiation side of the recording / reading light. This is advantageous in increasing the recording capacity due to the multilayering. In particular, in the present embodiment, since the refractive index of the recording layer 14 and the refractive index of the second intermediate layer 15B are substantially the same, the light reflectance at the second interface 18B is substantially zero, so The light can reach the recording layer 14 and is advantageous in increasing the recording capacity due to the multilayer structure.

In order to adjust the refractive indexes of the recording layer 14 and the intermediate layer 15, the composition of the materials used for the recording layer 14 and the intermediate layer 15 may be adjusted.
Specifically, since the material of the recording layer 14 includes a polymer binder and a dye, the refractive index of the recording layer 14 is selected by appropriately selecting the refractive index of the polymer binder and the dye and changing the blending ratio thereof. Can be adjusted arbitrarily. In addition, even if the polymer binder has a similar basic structure, the refractive index changes when the degree of polymerization is different, so a polymer binder with a different degree of polymerization can be used, or the degree of polymerization of the polymer binder can be adjusted. By doing so, the refractive index can be adjusted. Furthermore, it is also possible to adjust by blending a plurality of polymer binders. It is also possible to adjust the refractive index by adding a refractive index adjusting agent (such as inorganic fine particles).

  Moreover, when adjusting the refractive index of the intermediate | middle layer 15, a refractive index can be adjusted by adjusting the polymerization degree of polymer materials, such as resin which can be used as a material of the intermediate | middle layer 15. FIG. It is also possible to adjust the refractive index by arbitrarily blending materials that can be used as the intermediate layer 15 or to adjust the refractive index by adding a refractive index adjusting agent (such as inorganic fine particles).

  The cover layer 16 is a layer provided to protect the recording layer 14 and the intermediate layer 15 and is made of a material that can transmit recording light, reading light, and reproducing light. The cover layer 16 is provided with an appropriate thickness of several tens of μm to several mm.

Next, a method for recording / reproducing information on the multilayer optical information recording disk 10 as described above will be described.
When recording information on a desired recording layer 14, as shown in FIG. 2, the recording layer 14 is irradiated with laser light (recording light RB) whose output is modulated in accordance with the information to be recorded. As an example, the wavelength of this laser beam is 405 nm. When the recording layer 14 has a multiphoton absorption compound as a recording dye, a pulsed laser beam that can increase the peak power may be used as the laser beam. The focal position of the recording light RB is not particularly limited, but can be in the vicinity of the first interface 18A, and preferably the recording layer 14 side is better than the first interface 18A.

  When the recording light RB is irradiated, a recording mark M (pit) is formed in which the center of the portion irradiated with the recording light RB has a convex shape from the recording layer 14 toward the first intermediate layer 15A. In detail, the recording mark M shown in FIG. 2 has a convex portion M1 at the center, and a ring-shaped concave portion M2 toward the recording layer 14 around the convex portion M1. The distance from the first interface 18A (first interface 18A before deformation) of the deepest portion of the recess M2 is smaller than the distance from the first interface 18A (first interface 18A before deformation) at the apex of the protrusion M1. . That is, the recording mark M as a whole can be said to be approximately convex. Note that the recording mark may be composed of only the convex portion M1 and the concave portion M2 may not be formed depending on the recording conditions.

  As shown in FIG. 3, when the recording mark M is irradiated with the reading light OB by a continuous wave laser, the reading at the first interface 18A is caused by the difference in the refractive index of the recording layer 14 and the refractive index of the first intermediate layer 15A. The light OB is reflected. At this time, a difference occurs in the intensity of the reflected light at the first interface 18A around the recording mark M and the recording mark M, so that the recording mark M can be detected by the difference in reflectance. Since the refractive index of the recording layer 14 is not changed from that before recording, the reflection of the reading light OB does not occur inside the recording layer 14 but occurs only at the first interface 18A, and the recording mark M is stabilized. Can be detected. For such optical detection, it is desirable that the convex portion M1 protrudes about 1 to 300 nm with respect to the interface (first interface 18A) before being deformed.

  In the present embodiment, since the recording mark M is formed with the concave portion M2 around the convex portion M1, when the reading light OB for reading the recording mark M is applied to the recording mark M, there is only the convex portion M1. Compared to the case, the intensity distribution of the reflected light by the recording mark M is considered to change abruptly according to the distance from the center of the convex portion M1, and can be read with a high degree of modulation.

  In the multilayer optical information recording disk 10 of the present embodiment described above, each recording layer 14 is formed with a groove 14A for performing tracking servo, so that tracking and recording / reproducing by one laser beam (recording / reading light) are performed. Is possible. As a result, information can be recorded and reproduced using an optical system similar to a conventional recording / reproducing apparatus for an optical information recording disk. Further, since each recording layer 14 has a groove 14A for performing tracking servo, it becomes possible to trace the track of the recording layer 14 with good reproducibility. Accordingly, for example, when recording is performed halfway through one recording layer 14, it becomes easy to perform recording from the continuation in the recording layer 14.

<Manufacturing method of multilayer optical information recording disk>
Next, a preferred method for manufacturing the multilayer optical information recording disk 10 of the present embodiment will be described with two examples.

[First Example of Manufacturing Method]
In the first example, as shown in FIG. 4A, first, the second intermediate layer 15B is formed on the surface of the first release sheet 21 on which the release agent is applied. Specifically, the second intermediate layer 15B can be formed, for example, by applying an ultraviolet curable resin on the first release sheet 21 and irradiating and curing the ultraviolet ray. The first release sheet 21 has a high release performance such that the force when peeling the first release sheet 21 is weaker than the force when peeling the second release sheet 22 described later. Is applied. In the present invention, the method for applying the material of each layer is not particularly limited, and for example, a spin coating method, a knife coating method, a roll coating method, a bar coating method, a blade coating method, a die coating method, a gravure coating method, etc. are adopted. can do.

  Next, the recording layer 14 is formed on the second intermediate layer 15B. Specifically, the recording layer 14 can be formed by applying a solution obtained by dissolving a polymer binder and a dye in a solvent on the second intermediate layer 15B and curing it by drying.

  Next, the first sheet S1 is obtained by forming the groove 14A on the surface of the recording layer 14 by thermal imprinting. Specifically, in this step, first, as shown in FIG. 4B, a thermal imprint mold 31 heated to a predetermined temperature is pressed against the surface of the recording layer 14 with a predetermined pressure. Next, the recording layer 14 is cooled, and then the mold 31 is peeled off from the recording layer 14, whereby the groove 14 </ b> A can be formed on the surface of the recording layer 14 as shown in FIG.

  The mold 31 is provided with a convex portion obtained by inverting the shape of the groove 14 </ b> A formed on the surface of the recording layer 14. In the present invention, the method for forming the mold is not particularly limited. For example, a mold is formed by electroforming using a metal material such as nickel, or a resist is applied to a material such as nickel, quartz, or silicon. For example, a method of forming irregularities by performing etching after printing can be employed.

  At the time of thermal imprinting of the recording layer 14, the mold 31 is preferably heated to Tg ± 25 ° C. with the glass transition temperature of the recording layer 14 being Tg [° C.]. Further, at the time of thermal imprinting of the recording layer 14, the mold 31 is preferably pressed against the recording layer 14 with a pressure of 0.1 MPa or more, and more preferably pressed with a pressure of 1 MPa or more.

  Next, as shown in FIG. 5A, the first intermediate layer 15A is formed on the surface of the second release sheet 22 prepared separately from the first release sheet 21 on the surface to which the release agent is applied. Thus, the second sheet S2 is obtained. Specifically, the first intermediate layer 15 </ b> A can be formed by applying an adhesive on the second release sheet 22. In the present invention, the order of producing the first sheet S1 and the second sheet S2 is not particularly limited.

  Next, the recording layer 14 of the first sheet S1 and the first intermediate layer 15A of the second sheet S2 are bonded together so that the second sheet S2 is superimposed on the first sheet S1, and the groove of the recording layer 14 is stacked. A first intermediate layer 15A is formed on the surface on which 14A is formed, and a third sheet S3 as shown in FIG. 5B is obtained.

  Next, as shown in FIG. 5C, the first release sheet 21 is removed from the third sheet S3 to expose the second intermediate layer 15B. As described above, since the first release sheet 21 is easier to peel than the second release sheet 22, only the first release sheet 21 is favorably removed without peeling off the second release sheet 22. Can do. Then, as shown in FIG. 5D, a recording layer 14 is newly formed on the exposed second intermediate layer 15B.

Next, as shown in FIGS. 6A and 6B, a groove 14A is formed on the surface of the newly formed recording layer 14 (exposed recording layer 14) by thermal imprinting, thereby forming a multilayer. A fourth sheet S4 as a sheet is obtained. The specific method of thermal imprinting in this step is the same as that in the step of obtaining the first sheet S1 described above, but when pressing the mold 31, the position of the groove 14A to be formed from now on, The position of the mold 31 is adjusted so that the position of the groove 14 </ b> A formed in the step of obtaining the first sheet S <b> 1 desirably matches with the accuracy within 25 μm in the radial direction.
The fourth sheet S4 obtained as described above is wound and stored in a roll shape, and is pulled out as much as necessary when used.

  Next, as shown in FIG. 7A, a substrate 11 is prepared, and a first intermediate layer 15 </ b> A (adhesive layer) is formed on the substrate 11. On the other hand, the fourth sheet S4 wound in a roll shape is pulled out and punched out according to the shape of the substrate 11. Then, the exposed recording layer 14 of the punched fourth sheet S4 is bonded to the first intermediate layer 15A formed on the substrate 11, and as shown in FIG. The first intermediate layer 15A, the recording layer 14, the second intermediate layer 15B, the recording layer 14, and the first intermediate layer 15A are formed in this order from the bottom.

  Next, as shown in FIG. 7 (c), the second intermediate sheet 15A is exposed by removing the second release sheet 22 from the fourth sheet S4 adhered on the substrate 11, and is punched here. By bonding the exposed recording layer 14 of the other fourth sheet S4, the recording layer 14, the second intermediate layer 15B, the recording layer 14, and the first recording layer 14 are formed on the substrate 11 as shown in FIG. Two unit structures (fourth sheet S4) composed of one intermediate layer 15A are stacked.

  Note that when the fourth sheet S4 is bonded to the substrate 11 or when the fourth sheet S4 is bonded to another fourth sheet S4, for example, the position of the hole formed in the center of the substrate 11 is used. And the position of the hole formed at the center of the fourth sheet S4 at the time of punching. In addition, when the fourth sheet S4 is bonded to the other fourth sheet S4, the position of the groove 14A of one fourth sheet S4 and the position of the groove 14A of the other fourth sheet S4 are determined. It is desirable to match with a precision within 25 μm in the radial direction.

Thereafter, the second release sheet 22 is removed from the uppermost fourth sheet S4 on the substrate 11 to expose the first intermediate layer 15A, and another fourth sheet punched therein is further removed. The step of attaching the exposed recording layer 14 in S4 is repeated as many times as necessary.
Finally, as shown in FIG. 7 (e), the second release sheet 22 is removed from the uppermost fourth sheet S4 on the substrate 11 to expose the first intermediate layer 15A. By laminating the layer 16, the multilayer optical information recording disk 10 including a plurality of recording layers 14 as shown in FIG. 1 can be manufactured.

  In the first example of the manufacturing method described above, the fourth sheet S4 is punched into the shape (disk shape) of the substrate 11 when the fourth sheet S4 is used. However, the present invention is not limited to this. It is not something. For example, as shown in FIGS. 8A to 8C, the blade 32B for punching is formed in, for example, a cylindrical shape in the mold 32 used in the step of obtaining the fourth sheet S4, and the fourth sheet S4 is formed. In the step of obtaining the recording layer 14, the recording layer 14 and the intermediate layer 15 may be cut into a disk shape simultaneously with the formation of the groove 14A by pressing the mold 32. According to this, since the manufacturing process can be reduced as compared with the case where thermal imprinting and punching are performed separately, the productivity of the multilayer optical information recording disk 10 can be improved.

[Second Example of Manufacturing Method]
In the second example, as shown in FIG. 9A, first, the recording layer 14 is formed on both surfaces of the second intermediate layer 15B (for example, polycarbonate formed in a sheet shape, for example) to form a resin sheet RS. Get. Note that both of the recording layers 14 may be formed at the same time, or one of them may be formed.

Next, as shown in FIG. 9B, grooves 14A are simultaneously formed on the surface of each recording layer 14 of the resin sheet RS by thermal imprinting.
Here, an example of the thermal imprint apparatus used in this process (thermal imprint process) will be briefly described. As shown in FIG. 10, the thermal imprint apparatus 40 includes a pair of transfer mechanisms 40 </ b> A and 40 </ b> B arranged side by side in the figure. Each of the transfer mechanisms 40A and 40B mainly includes an endless belt 42 provided with a plurality of molds 41 and a plurality of rollers 43 to 47 around which the endless belt 42 is stretched. The thermal imprint apparatus 40 transfers the convex shape of the mold 41 to each recording layer 14 when the resin sheet RS conveyed from the left to the right in the drawing passes between a pair of rotating endless belts 42. Then, the groove 14A is formed simultaneously on the surface of each recording layer 14. At this time, the mold 41 is heated to a predetermined temperature before entering between the pair of pressure rollers 44, and is pressed between the pair of pressure rollers 44 against the resin sheet RS (recording layer 14) with a predetermined pressure. Hit. Thereafter, the mold 41 is cooled while being conveyed toward the peeling roller 45 from between the pair of pressure rollers 44 while being in close contact with the recording layer 14, and is peeled off from the recording layer 14 by the peeling roller 45.

  As shown in FIG. 11A, in this embodiment, at the time of thermal imprinting, the positioning mark 14M is positioned at the center C (multilayer light) of the groove forming area 14G simultaneously with the formation of the groove 14A (groove forming area 14G). One corresponding to the center of the information recording disk 10) is formed at both ends of the resin sheet RS. This positioning mark 14M is obtained by transferring a convex portion (not shown) obtained by inverting the shape of the positioning mark 14M formed on each mold 41 (see FIG. 10) by thermal imprinting. Each is transferred to the recording layer 14). In the case of the thermal imprinting process in this example, first, thermal imprinting is experimentally performed on the resin sheet RS. As shown in FIG. 11B, the positioning mark 14M (see the solid line) on the recording layer 14 on one side and the positioning mark 14M (see the broken line) on the recording layer 14 on the other side deviated beyond a predetermined range. In this case, by adjusting the position of each endless belt 42 and / or mold 41 of the thermal imprint apparatus 40 shown in FIG. 10, the position of the positioning mark 14M on both sides (the position of the groove 14A on both sides) is matched. Then, after the positions of the positioning marks 14M on both sides are matched within a predetermined range, thermal imprinting is performed on the product resin sheet RS. The position of the groove 14A on one side and the position of the groove 14A on the other side are preferably matched with accuracy within 25 μm in the radial direction, and more preferably matched with accuracy within 10 μm.

Next, as shown in FIG. 9C, a first intermediate layer 15A is formed on the release sheet 22 to obtain a second sheet S2 (fifth sheet). Note that the second sheet S2 may be prepared and prepared in advance.
Next, the first intermediate layer 15A of the second sheet S2 is bonded to one of the recording layers 14 on which the grooves 14A are formed, so that the resin sheet RS is overlaid on the second sheet S2, and FIG. As shown, the first intermediate layer 15A is formed on the surface of the one recording layer 14 on which the groove 14A is formed to obtain a fourth sheet S4 (sixth sheet) as a multilayer sheet.
The fourth sheet S4 obtained as described above is wound and stored in a roll shape, and is drawn out as much as necessary.

  Thereafter, as in the case of the first example described above, as shown in FIGS. 7A to 7E, the first intermediate layer 15A formed on the substrate 11 is punched in accordance with the shape of the substrate 11. The fourth sheet S4 is pasted and another step of pasting another fourth sheet S4 punched thereon is repeated. Finally, the cover layer 16 is pasted, so that the multilayer light as shown in FIG. The information recording disk 10 can be manufactured.

  In the second example of the manufacturing method described above, the fourth sheet S4 is punched into the shape of the substrate 11 when using the fourth sheet S4. However, the present invention is not limited to this. . For example, in the thermal imprint apparatus 40 shown in FIG. 10, a punching blade is formed on the mold 41 or the endless belt 42, and simultaneously with the formation of the groove 14A in the thermal imprint process, the recording layer 14 and the intermediate layer 15 are formed. As shown in FIGS. 12A and 12B, a cut 14C may be formed in the recording layer 14 and an intermediate layer (not shown). In this case, since the resin sheet RS has already been punched into a disk shape, in the process of obtaining the fourth sheet S4, the punched individual portions (each groove forming region 14G) were punched into a disk shape. A fourth sheet S4 is obtained by pasting the second sheet S2 (see FIGS. 9C and 9D).

  Incidentally, as shown in FIG. 12B, the non-use area is obtained by punching the resin sheet RS so that the area around the groove forming area 14G (corresponding to the non-use area 14D in FIG. 12A) is connected to each other. 14E can be collectively separated from the use area (groove formation area 14G). Further, in the first example of the manufacturing method described above, when punching out the fourth sheet S4, as shown in FIG. 12B, by punching out the areas around the groove forming area 14G, The unused area 14E can be removed from the second release sheet 22 at once.

  Further, in the above-described examples of the two manufacturing methods, as shown in FIGS. 7A to 7E, after the first intermediate layer 15A is formed on the substrate 11, the fourth sheet S4 is laminated, and finally The multilayer optical information recording disk 10 is manufactured by attaching the cover layer 16 to the optical disk, but the present invention is not limited to this. For example, after the first intermediate layer 15A of the fourth sheet S4 is bonded to the substrate 11 and another fourth sheet S4 is stacked, the uppermost recording layer 14 of the fourth sheet S4 is stacked. The multilayer optical information recording disk 10 may be manufactured by forming the first intermediate layer 15A (adhesive layer) and bonding the cover layer 16 together. In addition, after the first intermediate layer 15A of the fourth sheet S4 is bonded to the substrate 11 and another fourth sheet S4 is stacked, the uppermost recording layer 14 of the fourth sheet S4 is positioned. In addition, the multilayer optical information recording disk 10 may be manufactured by bonding the first intermediate layer 15A of the cover layer 16 on which the first intermediate layer 15A (adhesive layer) is formed.

  In the above-described two manufacturing method examples, the mold is heated during the thermal imprinting. However, the present invention is not limited to this. For example, the recording layer 14 (sheet including the recording layer 14) is used. May be heated, or both the mold and the recording layer 14 may be heated.

  According to the manufacturing method of the multilayer optical information recording disk 10 described above, since the multilayer optical information recording disk 10 in which each recording layer 14 has the groove 14A can be manufactured, tracking and recording / reproducing by one laser beam is possible. In addition, the track of the recording layer 14 can be traced with good reproducibility. Further, since the groove 14A can be easily formed in the recording layer 14 by thermal imprinting, the multilayer optical information recording disk 10 in which each recording layer 14 has the groove 14A can be manufactured at a relatively low cost.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented.

  For example, in the above embodiment, the recording layer 14 includes a polymer binder and a dye dispersed in the polymer binder. However, the present invention is not limited to this, and the recording layer has a dye bonded thereto. It may also contain a polymer. Specifically, examples of the polymer to which the dye is bonded include a compound having a structure represented by the following general formula (2).

(In general formula (2), Y represents a substituent in which both Hammett's sigma para value (σp value) has a value of zero or more, and X also represents the same kind of substituent. N represents an integer of 1 to 4, R ₁ , R ₂ and R ₃ represent substituents, and may be the same or different, l is 1 or more, and m is an integer of 0 to 4. .)

  In the embodiment, only one side (first intermediate layer 15A) of the intermediate layer 15 adjacent to the recording layer 14 is made of an adhesive. However, the present invention is not limited to this, and FIG. ), The intermediate layer 15 adjacent to the recording layer 14 is both made of an adhesive, and the multilayer optical information recording disk 20 includes an intermediate layer 15 made of an adhesive between the substrate 11 and the cover layer 16. The recording layer 14 may be arranged alternately. In this case, the thickness of the single recording layer 14 is preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 7 μm or more so that interlayer crosstalk does not occur. Further, the upper limit of the thickness of the recording layer 14 is not particularly limited. However, in order to increase the number of recording layers 14 as much as possible, a thinner one is desirable as long as interlayer crosstalk does not occur. For example, 20 μm or less is desirable. In this case, the groove 14A for performing the tracking servo is formed on both interfaces 18 of the recording layer 14. The recording layer 14 having the groove 14A on both interfaces 18 is, for example, as described above. In the thermal imprint process (see FIG. 9B) of the second example of the manufacturing method, a recording layer sheet 14S consisting only of the recording layer 14 as shown in FIG. 13B is used instead of the resin sheet RS. It can be formed by performing thermal imprinting.

  According to the configuration in which both of the intermediate layers 15 adjacent to the recording layer 14 are made of an adhesive, the recording mark M (convex shape) can be formed on both the interfaces 18 of the single recording layer 14. As a result, for example, when the number of recording layers 14 is the same as that of the multilayer optical information recording disk 10 described above, the recording capacity can be increased, and the number of recording layers 14 can be increased. Even when the number is less than 10, an equivalent recording capacity can be realized.

  In the above embodiment, information is recorded on the convex portion 14B (land) between the grooves 14A and 14A formed on the recording layer 14 (the recording mark M is formed), but the present invention is not limited to this. The multilayer optical information recording disk may record information on a groove and perform tracking servo using a land between adjacent grooves.

Next, an experiment for confirming that a groove can be formed on the surface of the recording layer by thermal imprinting will be described.
<Production of multilayer sheet>
A multilayer sheet including a recording layer (Tg 73 ° C.) and an intermediate layer composed of an adhesive was prepared by the following method and conditions. In addition, the multilayer sheet of the present example has a first intermediate layer and a recording layer (hereinafter referred to as a first recording layer) in order from the second release sheet side on a second release sheet (thickness: 38 μm). And a second intermediate layer and a recording layer (hereinafter referred to as a second recording layer) (in the fourth sheet S4 shown in FIG. 6B, the groove 14A is not formed). Is the same structure).

The second intermediate layer is 79 parts by mass of acrylic resin EA-F5003 (manufactured by Osaka Gas Chemical Co., Ltd.), 21 parts by mass of acrylic resin M-310 (manufactured by Toagosei Co., Ltd.), photopolymerization initiator IRGACURE184 (manufactured by Ciba AG) 3 The mass part was mixed by stirring for 5 hours, and the material (UV curable resin) was prepared first. Then, the UV curable resin is blade-coated on the first release sheet HY-NS80 (Higashiyama Film Co., Ltd.) and irradiated with ultraviolet rays using a high pressure UV lamp UM-102 (Ushio Electric Co., Ltd.). Formed.
The first recording layer is composed of 63 parts by mass of polymethyl methacrylate (manufactured by Sigma Aldrich Japan Co., Ltd.) as a polymer binder, and 2,2 ′, 4,4′-tetrahydroxybenzophenone (Sigma Aldrich Japan) as a light absorbing material (dye). 37 parts by mass) was added to 2200 parts by mass of the solvent 2-butanone (manufactured by Wako Pure Chemical Industries, Ltd.) and dissolved by stirring for 20 hours. First, a recording layer coating solution was prepared. Then, the recording layer coating solution was applied onto the second intermediate layer by blades and dried in an oven at 100 ° C. for 3 minutes.

The first intermediate layer is sandwiched between a pair of release sheets (one is a second release sheet) from a 10 μm thick adhesive sheet DA-3010 (manufactured by Hitachi Chemical Co., Ltd.) and the other release sheet (light release) Sheet) was peeled off and bonded to the first recording layer using a laminator RSL-382S (manufactured by Japan Office Laminator Co., Ltd.).
For the second recording layer, the first release sheet in contact with the second intermediate layer is peeled off, and the above-mentioned recording layer coating solution is applied onto the second intermediate layer by blades and dried in an oven at 100 ° C. for 3 minutes. To form.
In addition, when the thickness of each layer was measured using a stylus type surface shape measuring instrument DektakXT (manufactured by ULVAC, Inc.), the thickness of the second intermediate layer was 10 μm, and the first recording layer and the second recording layer Each thickness was 0.4 μm.

<Thermal imprint>
Thermal imprinting was performed on the second recording layer by the following method and conditions. In this embodiment, thermal imprinting is not performed on the first recording layer.
A nickel mold was prepared by electroforming. The transfer surface of the mold has a circular shape with a radius of 69 mm, and a convex portion in which the shape of the groove is reversed is formed within an annular range of 24 to 58 mm from the center. The mold was formed in a single spiral land and groove shape, the width of the convex part was 320 nm, the height was 60 nm, and the pitch was 640 nm.
As mold release treatment, the mold is immersed in Optool 2100 (manufactured by Daikin Industries, Ltd.) and then rinsed with a fluorine solvent HD-TH (manufactured by Daikin Industries, Ltd.) to form a monomolecular fluorine film on the mold surface. did.
The mold was overlaid on the second recording layer, evacuated, and then heated. And after reaching 70 degreeC, it pressurized to 3 Mpa and hold | maintained for 3 minutes. Thereafter, the temperature was lowered to 35 ° C., the pressure was released, and the mold was peeled from the second recording layer.

<Measurement method>
The surface of the second recording layer after thermal imprinting was measured with an AFM (atomic force microscope) under the following conditions.
Apparatus: Scanning probe microscope OLS3500 (manufactured by Olympus Corporation)
AFM probe: AR5-NCHR-20 (manufactured by NanoWorld AG)
Measurement conditions: Dynamic mode Scanning range: 2 μm × 2 μm

<Experimental result>
As shown in FIGS. 14A and 14B, when the surface of the second recording layer after thermal imprinting was observed using an AFM, grooves on the surface of the second recording layer (see FIG. 14A) It was confirmed that a dark portion (see dark part) was formed. The width of the groove is about 0.36 μm, the width of the land is about 0.30 μm, the distance from the center of the groove in the radial direction to the center of one land is about 0.33 μm, and the depth of the groove is About 50 nm.

Claims (6)

A method for producing a multilayer optical information recording disk comprising a plurality of recording layers and an intermediate layer provided between the plurality of recording layers ,
Or comprising a dye dispersed in a polymeric binder and the polymer binder, or, forming a rig Lube by the thermal imprinting on the surface of the recording layer containing the dye is bound polymer,
Obtaining a multilayer sheet comprising an intermediate layer composed of the pressure-sensitive adhesive and the recording layer to form an intermediate layer made of tacky adhesive on said grooves are formed plane of the recording layer,
And a step of bonding the multilayer sheet to another multilayer sheet. A plurality of recording layers, and an intermediate layer provided between the plurality of recording layers, wherein the intermediate layer adjacent to one side of the recording layer is a first intermediate layer made of an adhesive, A method for producing a multilayer optical information recording disk , wherein the intermediate layer adjacent to the other side is a second intermediate layer harder than the first intermediate layer ,
On the first release sheet, forming a second intermediate layer, either containing a dye dispersed in a polymeric binder and the polymer binder, or a recording layer containing a dye is bonded polymer in this order And a process of
Obtaining a first sheet by forming a rig Lube by the thermal imprinting on the surface of the recording layer,
Forming a first intermediate layer on the second release sheet to obtain a second sheet;
A step of laminating the second sheet on the first sheet to obtain a third sheet by laminating the first intermediate layer and the recording layer;
Forming a recording layer on the second intermediate layer exposed by removing the first release sheet from the third sheet;
Obtaining a fourth sheet by the surface of the exposed portion of the recording layer to form a rig Lube by the thermal imprinting,
And a step of bonding the fourth sheet to another fourth sheet. A plurality of recording layers, and an intermediate layer provided between the plurality of recording layers, wherein the intermediate layer adjacent to one side of the recording layer is a first intermediate layer made of an adhesive, A method for producing a multilayer optical information recording disk , wherein the intermediate layer adjacent to the other side is a second intermediate layer harder than the first intermediate layer ,
Forming a recording layer containing a polymer binder and a dye dispersed in the polymer binder on each of both surfaces of the second intermediate layer , or a polymer having a dye bonded thereto ;
A step of simultaneously forming by rig Lube Hot imprint on the surface of each recording layer,
Forming a first intermediate layer on the release sheet to obtain a fifth sheet;
A step of obtaining a sixth sheet by bonding the first intermediate layer of the fifth sheet to one recording layer;
And a step of bonding the sixth sheet to another sixth sheet. The glass transition temperature of the recording layer as Tg [° C.], either at least one of thermal imprint mold and the recording layer during thermal imprinting claim 1, characterized in that heating to Tg ± 25 ° C. of claim 3 A method for producing a multilayer optical information recording disk according to claim 1 . The method for producing a multilayer optical information recording disk according to any one of claims 1 to 4 , wherein the thermal imprint mold is pressed against the recording layer at a pressure of 0.1 MPa or more. Obtaining the fourth sheet, the pressing of the thermal imprint mold, simultaneously with the formation of the grooves, according to claim 2, characterized in that cutting the recording layer and the intermediate layer into a predetermined shape A method of manufacturing a multilayer optical information recording disk.

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